Ratchet mechanism for timepieces



Sept. 20, 1949.

A. a. POOLE RATCHET MECHANISM FOR TIMEPIECES Filed Aug. 10. 1948 Patented Sept. 20, 1949 UNITED STATES PATENT OFFICE RATCHET MECHANISM FOR TIMEPIECES Arthur B. Poole, Harwinton, Conn.

Application August 10, 1948, Serial No. 43,405

10 Claims.

The present invention relates in general to ratchet-mechanisms and more especially to an improved pawl for the ratchet-mechanism of a timepiece.

An object of the invention is to provide a superior ratchet-mechanism which may be manufactured of parts which are easily fabricated and of dependable and durable construction.

A further object of the invention is to provide a superior ratchet-mechanism for timepieces wherein a double-ended pawl is provided which is positively actuated at all times by the teeth of a ratchet-wheel as the latter is rotated relative to a drive-wheel, thereby insuring immediate lock ing action between the drive-wheel and the ratchet-Wheel when the latter is rotated in t e direction of rotation of the drive-wheel.

With the above and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a front elevation of a ratchet-mechanism constructed in accordance with the present invention with one pawl-finger against the perpendicular face of a tooth of the ratchet-wheel;

Fig. 2 is an edge View of the ratchet-mechanism cially to an arbor ill of one of the drive-springs of a timepiece. A ratchet-wheel II is mounted on the arbor l U substantially intermediate its opposite ends and is adapted to be fixedly secured thereon by any suitable fastening-means such as, for example, a force or drive fit, the ratchetwheel comprising a set of peripheral teeth l2, each tooth having a tangential or sloping face l3 and a radial face M, the latter being substantially per-- 7 pendicular to the sloping face l3 of the next It) in juxtaposition to and preferably against one side of the ratchet-wheel H is a drive-wheel l5 constituting a drive-gear for transmitting the power of a Wound spring (not shown) to the timetrain or alarm-train of the timepiece, as th case may be.v As shown especially well in Fig. 5, the drive-wheel I5 is provided with a pair of elongated substantially-rectangular clearance-apertures IS in diametrically-opposed relationship, the longitudinal axes of the apertures being in alignment and extending radially from the center of the wheel. As related to the ratchet-wheel H and more particularly to the over-all diameter of its teeth I2, the loci of the outer end of the teeth coincide with a circumferential line about the center of the drive-gear wheel and of a diameter to intersect each radial clearance-aperture it substantially intermediate its opposite ends.

The double-ended pawl of this invention is shown especially well in Fig. 6 and comprises a substantially-rectangular plate I! having an elongated central aperture l8, the longitudinal axis of which coincides with the longitudinal axis of the plate IT. The transverse dimension of the aperture I8 is slightly greater than the diameter of the arbor it], as shown especially well in Figs. 1 and 3, so that when the pawl-plate H is mounted thereon, the plate will have substantially no lateral movement relative to the arbor. The opposite ends of the elongated aperture I8 are rounded as shown, and the over-all length of the elongated aperture is considerably greater than the diameter of the arbor, whereby the pawl-plate may enjoy appreciable rectilinear movement in a plane parallel to the plane of the drive-Wheel and in the. direction of the common longitudinal axis of the said radial clearance-apertures [6.

For the purpose of brevity, this rectilinear movement of the pawl-plate is hereinafter referred to as its transverse movement relative to the drive-wheel l5.

At each end of the pawl-plate I! is a pawl-finger indicated generally at l9, each finger comprising the outer free end of a substantially-rectangular tang 20 cut from or otherwise formed at the corresponding end of the pawl-plate, the outer free end I9' of each tang being bent up at substantially right angles to the plane of the Plate.

Each pawl-finger l9 thus constitutes a substantially-rectangular block-like member, the width of which, as shown especially well in Fig. 3, is less than the transverse dimension of a radial clearance-aperture l6 of the drive-wheel, while the longitudinal dimension of each pawl-finger is successive tooth. Mounted freely on the arbor 55 considerably less than the longitudinal dimension of a radial clearance-aperture l6. Consequently, when the pawl-fingers extend through their respective clearance-apertures N5 of the drivewheel, as hereinafter described, the fingers l 9 will engage freely therein and have appreciable longitudinal movement with respect thereto, that is to say, movement transversely of the drive-wheel.

As shown in Fig. 4, the pawl-plate H is adapted to be mounted freely on the arbor l9 in juxtapositiontoand preferably against the adjacent side of the drive-wheel l5 opposite that side which is in juxtaposition to the ratchet-wheel, with the fingers IQ of the pawl-plate extending through the respective radial clearance-apertures it of the drive-wheel f5 into cooperative engagement with the teeth I 2 of the. ratchetwheel, the pawl-plate I! being effectively held from movement longitudinally on the arbor 10 away from the drive-wheel by means of aretaining-collar 2| which is fixedly secured to the arbor i5 and engages against the outside face of the pawl-plate IT.

Referring especially to Figs. 1 and 3, it will be noted that the distance between the inner faces 22 of the respective pawlafin'gers l9 measured on the longitudinal axis of the pawl-plate IT, is slightly less than the over-all diameter of the ratchet-wheel. In accordance: with this constructi'on, the inner faces 22 of the respective pawl-fingers ['9 are adapted to be moved positively into operative engagement with each successive tooth l2 of the ratchet-wheeL Thus, when the inner face 22 of the upper pawl-finger I9 of Fig. 3 just clears the point of the upper tooth I2 of the ratchet-wheel, the inner face 22 of the lower pawl-finger f9 will be in camming engagement with the slopin face I3 of its respective tooth of the ratchet-wheel, and hence when the ratchet-wheel H is rotated counterclockwise, as indicated. in Fig. 3, the lower pawlfinger will be cammed downwardly positively to a position such that its inner face 22 clears the point of its respective tooth [2' of the ratchetwheel while the upper pawl-finger will have been drawn downwardly in rear of the perpendicular face of its respective tooth for subsequent engagement by the sloping surface of the next succeeding ratchet-tooth. Further rotation of the ratchet-wheel in a counterclockwise direction thereupon causes the upper pawl-finger [9 to be cammed upwardly transversely with respect to the drive-wheel l5 thereby simultaneously pulling the lower pawl-finger upwardly positively in rear of the substantially-perpendicular face of its respective ratchet-tooth. Since the perpendicular faces M of the respective ratchet-teeth [2 are moving away from the corresponding pawlfingers IQ of the pawl-plate, the ratchet-wheel imparts substantially rectilinear movement only to the pawl-plate.

Specifically, when the arbor [U is rotated counterclockwise as, for example, when winding 9, spring of the timepiece, the ratchet-wheel ll rotates in the direction of the arrow in Figs. 1 and 3, and relative to the drive-wheel [5, the latter being disconnected therefrom by reason of the direction of rotation of the ratchet-wheel with respect thereto and the resulting rectilinear movement of the double-ended pawlplate H, as hereinabove described. Since the pawl-plate is operatively connected to the drive-wheel by engagement of its pawl-fingers f9ll9 in the radial clearance-apertures l6-l6 thereof, the pawl-plate is thereby restrained from rotating but, on the other hand, is free to enjoy rectilinear movement transversely with respect to the drivewheel because of the construction of the pawlfingers which permits them to move transversely freely in the clearance-apertures [6 of the drivewheel. Thus, as each pawl-finger I9 is succes sively engaged by the sloping faces of the succeeding teeth I2 of the ratchet-wheel, the pawl plate I! is reciprocated transversely of the drivewheel with at least one finger of the pawl-plate being in engagement positively with a tooth of the. ratchet-wheelthroughout the rotation thereof.

However, when the arbor I0 is rotated in the opposite direction, or clockwise, as, for example, by the force of a wound spring, then the pawlfinger I9, which is in the path of an oncoming perpendicular face IA of one of the teeth of the ratchet-wheel, will be engaged thereby and subjectedtoa shearing strain between the perpendicular face of that particular ratchet-tooth and the wall of the clearance-aperture l6 of the drive-wheel through which the finger projects, as a consequence of which the drive-wheel will be eifectively locked to the ratchet-wheel and rotated thereby in a clockwise direction for driving the time-train or alarm-train of the timepiece, as the case may be.

From the foregoing it will be. seen that the invention provides a superior pawl-mechanism embodyin a single double-ended pawl-plate such that its fingers are positively engaged at all times with the teeth of the ratchet-wheel, the click action of the pawl-plate being positive and independent of a pawl-spring or other resilient member. Moreover, the pawl-plate and cooperating mechanism comprise durable elements which are easily fabricated and operable in a simple and efficacious manner.

The invention may be carried out in other specific ways than those herein set. forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. In a ratchet-mechanism, the combination with a ratchet-wheel and a coaxial drive-wheel mounted in juxtaposition thereto with capacity for relative rotary movement, the said drivewheel having substantially diametrically-opposed radial clearance-apertures; of a pawlplate located in juxtaposition to said drive-wheel on the side thereof opposite said ratchet-wheel, said pawl-plate being movable transversely with respect to said drive-wheel and having diametrically-opposed fingers movable in and arranged to project through the radial apertures respectively of said drive-wheel into engagement with the teeth of said ratchet-wheel, said fingers being adapted thus to lock said drive-wheel to said ratchet-wheel for rotating said drive-wheel in the direction of rotation of said ratchet-wheel and to be moved positively into and out of engagement with successive teeth of said ratchetwheel when the latter is rotated relative to said drive-wheel.

2. In a ratchet-mechanism, the combination with a ratchet-wheel and a coaxial drive-wheel mounted in juxtaposition thereto with capacity for relative rotary movement, the said drive-wheel having substantially diametrically-opposed radial clearance-apertures; of a pawl-plate located in juxtaposition to said drive-wheel on the side thereof opposite said ratchet-wheel, said pawlplate having an elongated axial aperture to enable said pawl-plate to move transversely with respect to said drive-wheel, and diametrically-opposed fingers movable in and arranged to project through the radial apertures respectively of said drive-wheel into engagement with the teeth of said ratchet-wheel, said fingers being adapted thus to lock said drive-wheel to said ratchetwheel for rotating said drive-wheel in the direction of rotation of said ratchet-wheel and to be moved positively into and out of engagement with successive teeth of said ratchet-wheel when the latter is rotated relative to said drive-wheel.

3. In a ratchet-mechanism, the combination with a ratchet-Wheel and a coaxial drive-wheel mounted in juxtaposition thereto with capacity for relative rotary movement, the said drive-wheel having substantially diametrically-opposed radial clearance-apertures; of a pawl-plate located in juxtaposition to said drive-wheel on the side thereof opposite said ratchet-wheel, said pawlplate being movable transverselyvwith respect to said drive-wheel and having diametrically-opposed fingers formed substantially perpendicular to the plane thereof and movable in and arranged to project through the radial apertures respectively of said drive-wheel into engagement with the teeth of said ratchet-wheel, said fingers being adapted thus to lock said drive-wheel to said ratchet-wheel for rotating said drive-wheel in the direction of rotation of said ratchet-wheel and to be moved positively into and out of engagement with successive teeth of said ratchet-wheel when the latter is rotated relative to said drivewheel.

4. In a ratchet-mechanism, the combination with a ratchet-wheel and a coaxial drive-wheel mounted in juxtaposition thereto with capacity for relative rotary movement, the said drive-wheel having substantially diametrically-opposed radial clearance-apertures; of a pawl-plate located in juxtaposition to said drive-wheel on the side thereof opposite said ratchet-wheel, said pawlplate having an elongated axial aperture to enable said pawl-plate to move transversely with respect to said drive-wheel and a pair of diametrically-opposed fingers in alignment with the longitudinal axis of said elongated aperture, said fingers being formed substantially perpendicular to the plane of said pawl-plate and movable in and arranged to project through the radial apertures respectively of said drive-wheel into engagement with the teeth of said ratchet-wheel, said fingers being adapted thus to lock said drivewheel to said ratchet-wheel for rotating said drive-wheel in the direction of rotation of said ratchet-wheel and to be moved positively into and out of engagement with successive teeth of said ratchet-wheel when the latter is rotated relative to said drive-wheel.

5. In a ratchet-mechanism, the combination with a ratchet-wheel and a coaxial drive-wheel mounted in juxtaposition thereto with capacity for relative rotary movement, the said drive-Wheel having substantially diametrically-opposed radial clearance-apertures; of a pawl-plate located in juxtaposition to said drive-wheel on the side thereof opposite said ratchet-Wheel, said pawlplate being movable transversely with respect to said drive-wheel and having a pair of diametrically-opposed fingers movable in and arranged to project through the radial apertures respectively of said drive-wheel into engagement with the teeth of said ratchet-wheel, said fingers being spaced apart diametrically a distance slightly less than the over-all diameter of said ratchet-wheel such that when said ratchet-wheel is rotated relative to said drive-wheel, each finger of said pawl-plate will be successively moved positively into engagement with the perpendicular face of one tooth of said ratchet-wheel by the camming action of the oppositely-disposed finger with the sloping face of a second tooth of said ratchetwheel, the finger on engagement with the perpendicular face of the said one ratchet-tooth being subjected to shearing strain between the said perpendicular face .of said one tooth and the wall of its radial clearance-aperture in said drivewheel when said ratchet-wheel is rotated in the direction of rotation of said drive-wheel to effectively lock said Wheels together.

6. In a ratchet-mechanism, the combination with a ratchet-wheel and a coaxial drive-wheel mounted in juxtaposition thereto with capacity for relative rotary movement, the said drive-wheel having substantially diametrically-opposed radial clearance-apertures; of a pawl-plate located in juxtaposition to said drive-wheel on the side thereof opposite said ratchet-wheel, said pawlplate having an elongated axial aperture to enable said pawl-plate to move transversely with respect to said drive-wheel and having a pair of diametrically-opposed fingers movable in and arranged to project through the radial apertures respectively of said drive-wheel into engagement with the teeth of said ratchet-wheel, said fingers being spaced apart diametrically a distance slightly less than the over-all diameter of said ratchet-wheel such that when said ratchet-wheel is rotated relative to said drive-wheel, each finger of said pawl-plate will be successively moved positively into engagement with the perpendicular face of one tooth of said ratchet-wheel by the camming action of the oppositely-disposed finger with the sloping face of a second tooth of said ratchet-wheel, the finger in engagement with the perpendicular face of the said one ratchet-tooth being subjected to shearing strain between the said perpendicular face of said one tooth and the wall of its radial clearance-aperture in said drivewheel when said ratchet-wheel is rotated in the direction of rotation of said drive-wheel to effectively lock said wheels together.

7. In a ratchet-mechanism, the combination with a ratchet-wheel and a coaxial drive-wheel mounted in juxtaposition thereto with capacity for relative rotary movement, the said drive-wheel having substantially diametrically-opposed radial clearance-apertures; of a pawl-plate located in juxtaposition to said drive-wheel on the side thereof opposite said ratchet-wheel, said pawlplate being movable transversely with respect to said drive-wheel and having a pair of diametrically-opposed fingers formed substantially perpendicular to the plane thereof and movable in and arranged to project through the radial apertures respectively of said drive-wheel into engagement with the teeth of said ratchet-wheel, said fingers being spaced apart diametrically a distance slightly less than the over-all diameter of said ratchet-wheel such that when said ratchetwheel is rotated relative to said drive-wheel, each finger of said pawl-plate will be selectively moved positively into engagement with the perpendicular face of one tooth of said ratchet-wheel by the camming action of the oppositely-disposed finger with the sloping face of a second tooth of said ratchet-wheel, the finger in engagement with the perpendicular face of the saidpne ratchet-tooth ibeing subjected to shearing strain between the ;said perpendicular'face of said one tooth and the wall of 1 itsradial clearance-aperture in said .adrive-wheel when said ratchet-wheel is rotated thereof oppositesaid'ratchet-wheel, said pawlplatehaving an elongated axial aperture to enable saidpaWl-plate:tomovetransversely with respect to said drive-wheeland a pair of diametricallyopposed fingers tformed substantially perpendicu- ;lar to :the plane of said pawl-plate and in align- .ment withithe longitudinal axis of said elongated aperture said fingers being movable in and arranged to project through the radial apertures Iespectivelyof said drive-Wheel into engagement With the teeth of said ratchet-wheel, said fingers lbeing spaced apart diametrically a distance slightly less than the overall diameter of said ratchet-wheel such that when said ratchet-wheel .is rotated relative tosaid drive-Wheel, each finger of said pawl-plate will be selectively moved positively into engagement with the perpendicular face .of one tooth of said ratchet-Wheel by the .camming action of the oppositely-disposed finger with the sloping face of a second tooth of said ratchet-wheel, the finger in engagement with the perpendicular face of the said one ratchet-tooth being subjected to shearing strain between the said perpendicular face of said one tooth and the Wall of its radial clearance-aperture in said drivewheel when said ratchet-wheel is rotated in the direction of rotation of said drive-wheel to effectively lock said Wheels together.

9. In a ratchet-mechanism, the combination with an arbor; of a ratchet-wheel fixedly mounted on said arbor, a drive-wheel freely mounted on said arbor in juxtaposition to said ratchet-wheel, said drive-wheel having substantially diametrically-opposite radial clearanceapertures; and a pawl-plate mounted freely on said arbor in juxtaposition to said drive-wheel on 'diametrically opposed 'fing'ers movable in and arranged to' projet throiigh the radial apertures respectively of 'said drive 'wheel into engagement with the teeth of said ratchet-w'heel, each of said pawl-fingers being siibjectedsuccessively to shearing'strain between the-perpendicular face of the corresponding-ratchet tooth ofsaid'ratchet-wreel and the wall wits-corresponding radial clearanceaperture in said drive-wheel when said ratchetwheel isrotated in-the 'dire'ction'of rotation of said drive-wheel to eifectiv'ely lock said wheels 'together.

10. In a ratchet-mechanism, the combination with an arbor; of a ratchet-wheel fixedly mounted on said arbor, a drive-wheel freely 'mount'ed on-said ather in juxtaposition to said ratchet-wheel, said drive-Wheel having substantially diametrically-opposite radial clearanceapertures and apawl-platemoun'ted freely on said arbor in juxtaposition to said drive-wheel on the side thereof op osite said ratchet-wheel, said pawl-plate being movable transversely with respect to said drive-wheel and having a pair of -diametrically-opppseli fin'gers movable in and arranged to project through the radial apertures respectively of sai'd drive-"wheel into engagement with the teeth of -said'r'atchet-wheel, said fingers being spaced apart diame'trically a distance slightly less than the over-all diameter of said ratchet-wheel such that 'whensaid ratchet-wheel is rotated relative to said drive-wheel, each finger of-said pawl-platewfllbe "successively moved positively into engagement with the perpendicular face of one tooth of said ratchet-wheel by the camming action of the oppositely-disposed finger with the sloping face of a second tooth of said ratchet-wheel, the finger in engagement with the perpendicular face of the said one ratchet-tooth being subjected to shearing strain between the said perpendicular face of said one tooth and the wall of its radial clearance-aperture in said drivewheel when said ratchet-wheel is rotated in the direction of rotation of said drive-wheel to effectively lock said wheels together. 7

ARTHUR B. POOLE.

No references cited. 

